Type action arrangement

ABSTRACT

The keylevers, trip levers and sublevers of a powered type action arrangement are pivotally supported on common pivot rods and mounted in a single mounting bracket with the keylevers biased to a rest position by springs urging the trip levers against the keylevers. The normal rest position of the keylevers and keylever movement necessary to initiate printing are determined by a stop member limiting the movement of the trip levers, and the stop member has a cam-shaped cross-sectional configuration and is rotatable so as to vary the distance of keylever movement necessary to effect printing. The keylever depression is resisted by leaf springs secured to the mounting bracket for engagement by the trip levers, and the resisting pressure may be varied by a pressure adjusting mechanism for moving the leaf springs relative to the trip levers. Each depression of a keylever pivots the associated trip lever to move a cam carried on the associated sublever into engagement with a rotating power roll for driving the corresponding type bar in a printing movement. The engagement of the cams with the power roll is limited by a stop member which is part of an impression control mechanism, and the position of the stop member may be adjusted to uniformly vary the impact intensity of all the type bars. After a cam is disengaged from the power roll, the momentum imparted to the type bar continues its printing movement toward the platen against the urging of a return spring connected to the sublever for returning it to a rest position. The impact intensity of each type bar may be individually varied by controlling the tension of the return spring, and the mounting bracket has a plate with a plurality of holes associated with each type action for enabling the return spring to be stretched to different distances. To prevent the type bars from undergoing a printing movement when a carriage supporting the platen is in a left margin position, a bail is pivoted into blocking relation with the cams for restricting engagement with the power roll.

United States Patent Madison TYPE ACTION ARRANGEMENT [75] Inventor: Theodore N. Madison, Wethersfield,

Conn.

[73] Assignee: Litton Business Systems, Inc., New

York, NY.

[22] Filed: Feb. 16, 1973 [21] Appl. No.: 333,295

[52] US. Cl. 197/17, 197/98 [51] Int. Cl B4lj 23/08 [58] Field of Search 197/16, 17, 98, 110, 111

[56] References Cited UNITED STATES PATENTS 1,929,963 10/1933 Youngberg 197/17 X 2,441,375 5/1948 Schuyler 197/110 2,796,966 6/1957 Toeppen 197/17 2,971,625 2/1961 RiX 197/17 3,259,223 7/1966 Heidt et al.. 197/17 3,393,788 7/1968 Dodge 197/17 3,458,024 7/1969 Schaefer 197/17 3,578,128 5/1973 Frechette et al 197/17 3,623,587 11/1971 Link 197/17 3,715,022 2/1973 Riit et al. 197/17 X Primary Examiner-Robert E. Pulfrey Assistant Examiner-R. T. Rader Attorney, Agent, or Firm-Joseph R. Spalla [57] ABSTRACT The keylevers, trip levers and sublevers of a powered type action arrangement are pivotally supported on common pivot rods and mounted in a single mounting bracket with the keylevers biased to a rest position by springs urging the trip levers against the keylevers.

[451 Oct. 1,1974

The normal rest position of the keylevers and keylever movement necessary to initiate printing are deter mined by a stop member limiting the movement of the trip levers, and the stop member has a cam-shaped cross-sectional configuration and is rotatable so as to vary the distance of keylever movement necessary to effect printing. The keylever depression is resisted by leaf springs secured to the mounting bracket for engagement by the trip levers, and the resisting pressure may be varied by a pressure adjusting mechanism for moving the leaf springs relative to the trip levers. Each depression of a keylever pivots the associated trip lever to move a cam carried on the associated sublever into engagement with a rotating power roll for driving the corresponding type bar in a printing movement. The engagement of the cams with the power roll is limited by a stop member which is part of an impression control mechanism, and the position of the stop member may be adjusted to uniformly vary the impact intensity of all the type bars. After a cam is disengaged from the power roll, the momentum imparted to the type bar continues its printing movement toward the platen against the urging of a return spring connected to the sublever for returning it to a rest position. The impact intensity of each type bar may be individually varied by controlling the tension of the return spring, and the mounting bracket has a plate with a plurality of holes associated with each type action for enabling the return spring to be stretched to different distances. To prevent the type bars from undergoing a printing movement when a carriage supporting the platen is in a left margin position, a bail is pivoted into blocking relation with the cams for restricting engagement with the power roll.

8 Claims, 13 Drawing Figures PAIEmmum 1 1374 saw u or 6 TYPE ACTION ARRANGEMENT This invention relates to a power driven typewriter, and more particularly to a type action arrangement of a plurality of powered type actions.

In a power driven typewriter, a type bar is driven in a printing movement by a cam engaging a rotating power roll to effect movement of a sublever linked to the type bar. The cam is pivotally carried on the sublever, and printing is initiated by depressing a keylever to move a trip lever which pivots the cam into engagement with the power roll. Upon completion of the printing movement of the type bar, the sublever is returned to a rest position under the urging of a return spring, and the trip lever and the keylever are also returned to a rest position under the urging of another spring.

An object of the present invention is to provide a type action arrangement in which the keylevers, the trip levers and the sublevers of a plurality of type actions are mounted in a manner simplifying the construction and assembly of the type actions in a typewriter.

Another object of the invention is to provide a type action arrangement in which the distance of keylever depression necessary to initiate the printing operation of the type action may be easily adjusted to accommodate the typing characteristics of individual typists.

Still another object of the invention is to provide a type action arrangement in which the pressure necessary to depress a keylever to initiate a printing movement of a type bar may be easily adjusted.

Yet another object of the invention is to provide a type action arrangement wherein the force driving each type bar in a printing movement may be selectively adjusted by varying the tension of the associated return spring urging the sublever to a rest position.

An additional object of the invention is to provide a type action arrangement in which the force driving the type bars in a printing movement may be uniformly adjusted so as to uniformly vary the impact intensity of the type bars.

A further object of the invention is to provide a type action arrangement in which the printing movement of the type bars is restricted to prevent printing when a carriage reaches its limit of travel in a letter feed direction.

Still other objects, features and advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of a preferred embodiment of the invention, taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a diagrammatic side view of a type action arrangement constructed in accordance with the present invention;

FIG. 2 is a partial perspective view of the type action arrangement shown in FIG. 1 and illustrating the manner in which the spring tension urging each sublever to a rest position may be selectively adjusted;

FIG. 3 is a partial view of the type action arrangement of FIG. 1 and illustrating, in one condition, a mechanism for varying the distance of keylever depression necessary to initiate the operation of the powered type action;

FIG. 4 is a view similar to FIG. 3 and illustrating, in another condition, the mechanism for varying the distance of the keylever depression necessary to initiate the operation of the type action arrangement;

FIG. 5 is a partial view of the: type action arrangement shown in FIG. I, and illustrating a mechanism for selectively varying the pressure :required to depress a keylever to initiate the printing operation of a type action;

FIG. 6 is a partial cross-sectional view of the type action arrangement shown in FIG. 5 and illustrating the manner in which the depression of a keylever is resisted, and illustrating the pressure adjusting mechanism in one position;

FIG. 7 is a partial view of the keylever resisting arrangement shown in FIG. 6 with the pressure adjusting mechanism in another position to reduce the pressure required to depress the keylever;

FIG. 8 is a partial perspective view of the type action arrangement shown in FIG. 1 and illustrating an impression control mechanism for uniformly varying the force imparted to each type action during a printing operation;

FIG. 9 is a partial cross-sectional view of the arrangement shown in FIG. 8 with the impression control mechanism adjusted to minimize the force imparted to a type action during a printing operation;

FIG. 10 is a view similar to FIG. 9 with the impression control mechanism adjusted to the maximum force imparted to a type action during a printing operation;

FIG. 11 is a partial perspective view of the type action arrangement shown in FIG. 1 and illustrating a mechanism for restricting the force imparted to a poweredtype action when a carriage reaches its limit of travel in a letter feed direction;

FIG. 12 is a partial cross-sectional view of FIG. 11 and illustrating the mechanism for restricting movement of the type action in a normal rest position; and

FIG. 13 is a view similar to FIG. 12 and illustrating the condition of the mechanism when the carriage is at its limit of travel in a letter feed direction.

Referring now in detail to the figures in the drawing and more particularly to FIG. 1, there is shown one of a plurality of powered type actions in a type action arrangement, generally indicated at 11, for printing type characters or other symbols on a recording medium, not shown, which may desirably be located on a platen 13. The type characters 15, or other symbols to be printed are formed on a type head 17 which is carried on the end of a type bar 19, and the type bar 19 is supported for a printing movement from a rest position to the platen 13. As is conventional, printing is effected by impacting one of the type characters 15 against the recording medium, and the type bar 19 is driven in a printing movement to the printing position by depressing a type key 21 forming a portion of a keyboard to cause a key actuating means, generally indicated 23, to move a cam 25 into engagement with a power roll 27 which may be rotatably driven by a suitable motor, not shown. The cam 25 is pivotally supported on a type bar linkage, generally indicated 29, and drives the type bar 19 to the printing position as the cam 25 moves in engagement with the rotating power roll 27. The recording medium, and the motor for driving the power roll 25 are not shown since they form no part of the present invention and may be desirably conventional. Furthermore, other portions of the typewriter, including the drive for the power roll 27 are illustrated and described in a copending application entitled Typewriter Carriage Jam Precluding and Action Jam Release Mechanisms.

As shown, the type bar 19 is pivotably supported about a segment wire 31, as is conventional, and is driven by the cam 25 through the type bar linkage 29 which includes a sublever 33 which is pivotably supported and connected to the type bar 19 by a link 35. The type key 21 for operating the key actuating means 23 is carried on a keylever 37 which is pivotably supported and has a projecting finger 39 for rocking an L- shaped trip lever 41 which is also pivotably supported. The L-shaped trip lever 41 has one arm 43 which is contacted by the finger 39 while the end of the other arm 45 contacts a shoulder 47 of the pivotably supported cam 25 for moving it into engagement with the power roll 27. In the rest position, the type bar 19 is normally urged against a headrest 49 by a resilient biasing means in the form of a return spring 51, and the type key 21 is normally urged to a rest position by a resilient biasing means in the form of another spring 53. To insure that the type key 21 undergoes the same distance of depression each time the type action 11 is operated, the cam 25 has a rearward portion 55 which is urged against a stop 57 formed on the end of the sublever 33 by further resilient biasing means in the form of a spring 59 which is stretched between the cam 25 and a suitable projecting portion 61 of the sublever 33.

When the type key 21 is depressed to initiate the operation of the type action 11, the keylever 37 is pivoted downwardly so as to pivot the trip lever 41 clockwise and move the cam 25 into engagement with the rotat ably driven power roll 27. As the cam 25 is driven by frictional engagement with power roll 27, the sublever 33 is pivoted rearwardly away from the power roll 27 and against the urging of the spring 51 so as to drive the type bar 19 from the rest position and toward the printing position at the platen 13. The driving movement of the cam 25 continues until the rearward end 55 of the cam 25 engages a stop member 63, whereupon the cam 25 returns to the stop 57 of the sublever 33 under the urging of the spring 59 while the momentum of the type bar 19 continues to move it toward the platen 13 against the urging of the return spring 51. After the type character impacts against the platen 13, the type bar 19 is returned to the headrest 49 under the urging of the return spring 51 while the trip lever 41 and the keylever 37 are returned to the rest position under the urging of the spring 53.

From the foregoing, it is apparent that the proper operation of each type action in the type action arrangement lldepends upon the accurate alignment of the sublever 33, the keylever 37 and the trip lever 41 as well as the relative positioning of their pivot points. The levers 33, 37, 41 and the cam 25 are typically constructed from stamped, sheet-metal parts, and in the past at least some of these parts have often been mounted in separate castings cut with slots for guiding the levers 33, 37, 41 during pivotal movement. Moreover, the trip levers 41 have sometimes been pivotally carried by the keylevers. However, such prior art arrangements are undesirable because of the difficulty in assembling the arrangement in the typewriter and the dimensional instability. The different castings must be aligned relative to each other while being secured to the frame of the typewriter, and the vibrations accompanying the operation of the typewriter may cause a casting to become loosened, thereby necessitating realignment. Moreover, the greater the number of separate pivot points, the greater the difficulty in accurately positioning the pivot points relative to each other.

In accordance with the present invention, the abovementioned difficulties are avoided by providing the sublevers 33, the keylevers 37 and the trip levers 4] with common pivot points, and mounting the levers 33, 37, 41 ina single mounting bracket, generally indicated 65, so as to form a single unit suitable for installation in a typewriter frame without further adjustment. As more particularly shown in FIG. 2, the keylevers 37 are supported by a pivot rod 67, the trip levers 41 are supported by a pivot rod 69, and the sublevers 33 are supported by a pivot rod 71. The mounting bracket 65 has an L-shaped cross-sectional configuration with the lower portion extending toward the power roll 27, and with L-shaped end plates 73 having holes 75, 77 and 79 stamped therein for receiving the rods 67, 69, 71 respectively and properly positioning them relative to each other. The L-shaped end plates 73 are connected in spaced-apart relation by wall means composed of a top wall 81, bottom wall 83, a front wall 85, a back wall 87, a lower top wall 89 and a lower front wall 91, and the walls are provided with suitable slots 93 through which portions of the levers 37, 41, 33 are received and guided during pivotal movement.

To align the levers 33, 37, 41 relative to each other so as to insure proper operation of the type key actions 11, the walls 81-91 are provided with tab slots 95 for receiving tabs 97 projecting from the end plates 73 so as to locate the walls 81-91 relative to each other and to the end plates 73. After the walls 81-91 are located on the end plates 73, the tabs 95 are deformed so as to clamp the walls 81-91 to the end plates 73, thus forming a key action unit for mounting between a pair of side plates 98, 99 which serve as a portion of the typewriter frame. With the type action bracket 65 securely assembled as a single unit, no further alignment of the parts is necessary and any subsequent loosening of the bracket 65 relative to the side walls 99 of the typewriter will not alter the relative pivotal positioning or alignment of the levers 33, 37, 41.

As is conventional the type keys 21 forming the keyboard are arranged in rows of different heights, and to insure that the type keys 21 forming each row of the keyboard are raised to the same uniform level, a stop member 101 is provided for limiting the pivotal movement of the trip lever 41 under the urging of the spring 53, thereby limiting the movement of the keylever 37. As shown, the stop member 101 is located in the upper portion of the mounting bracket 65 beneath the pivot -rod 67 for the keylevers 37, and the stop member 101 is engaged by the back of the arm 43 of the trip lever 41. To enable the springs 53 to be secured to the mounting bracket 65 as part of a single key action unit for mounting to the side plates 98, 99, the mounting bracket 65 is provided with a forward plate 103 depending from the top wall 81 by a suitable tab and slot connection, generally indicated 105, and having a series of books 107 formed thereon to which the springs 53 are stretched from a hooked portion of the arm 45 of each trip lever 41. To guide the trip levers 41 during pivotal movement, the forward plate 103 has vertical slots 109 formed therein for receiving a nose 111 formed on the end of the trip lever arm 43.

In accordance with another feature of the invention, the type action arrangement is provided with a keylever control mechanism for enabling adjustment of the distance of keylever depression necessary to effect printing so as to accommodate the typing characteristics of different typists, and particularly typists accustomed to manual type actions. As more particularly shown in FIGS. 3 and 4, the stop member 101, which forms a portion of the keylever control mechanisms is in the form of a rod having a cross-sectional configuration in the shape of a cam and is rotatably supported in the mounting bracket 65 by holes 102 in the spaced-apart L-shaped end'plates 73. By rotating the stop member 101, the position of engagement with the trip lever 41 may be varied, and accordingly the normal level of the type key 21 may be adjusted between an upper limit, as shown in FIG. 3, and a lower limit, as shown in FIG. 4. When the normal level of the type key 21 is adjusted to the upper limit, as shown in FIG. 3, the type key 21 must be depressed a greater distance to move the cam 25 into engagement with the power roll 27 than when the normal limit of the type key 21 is adjusted to the lower position, as shown in FIG. 4.

To enable an operator to easily adjust the position of the stop member, the keylever control mechanism includes a dial 113 which is located at the keyboard area and operably connected to the stop member 101. As shown, the dial 113 is in the form of a disk which is rotatably supported about a shaft 115 and operates a link 117 which is pivotally connected to a crank 119 suitably attached to one end of the rotatably supported stop member 101. The link 117 is slidably supported about the shaft 115 which is received through a slot 121 formed in the link 117, and the dial 113 has a spiraling groove 123 formed therein for receiving a pin 125 projecting laterally from the link 117. Accordingly, rotation of the dial 113 effects a sliding movement of the link 117 which operates on the crank 119 to rotate the stop member 101 and vary the normal level of the type keys 21. To prevent the keylevers 37 from bouncing upwardly above the adjusted level when the type key 21 is released, a suitable stop 127 may be provided for limiting the upward movement of the keylevers 37. Although the stop 127 is shown as being in the form of a piece of cork held by a metal bracket, as is conventional, the stop 127 may be constructed from a suitable foam material capable of accommodating the different levels to which the type keys may be adjusted, or the stop 127 may be pivoted along with the stop member 101 by a suitable mechanism.

To enable the pressure required to depress a type key 21 to be selectively varied to accommodate the typing characteristics of different typists, the type action arrangement 11 is provided with a pressure control mechanism, generally indicated 129. As more particularly shown in FIGS. 5 and 6, the pressure control mechanism 129 includes a series of leaf springs 131 for resisting the depression of the keylevers 37 and a keyboard control member 133 for varying the resisting pressure exerted by the springs 131. The series of leaf springs 131 are attached to the front of the depending plate 103 by suitable means, for example rivets, with each spring 131 positioned in front of a slot 109 so as to be deflected by the nose 111 of a trip lever 41 when the associated type key 21 is depressed. To vary the resisting pressure provided by the leaf spring 131, the pressure control mechanism 129 includes an adjusting member 135 which is rotatably supported behind the depending plate 103 between the spaced-apart side plates 98, 99. The adjusting member 135 has a cross sectional configuration in the form of a cam so as to move the depending plate 103 from a position of maximum spring pressure, as shown in FIG. 6, to a position of minimal spring pressure, as shown in FIG. 7.

The keyboard control member 133 for varying the spring pressure resisting the depression of a type key 21 is in the form of a disk which is rotatably supported about the shaft 115 and operates a link 137 which is pivotally connected to a crank 139 attached to one end of the rotatably supported adjusting member 135. The link 137 is slidably supported about the shaft 115 which is received through a slot 141 formed in the link 137, and the disk 133 has a spiraling groove 145 formed therein for receiving a pin 147 projecting laterally from the link 137. The pressure control mechanism 129 is normally biased to a position of minimum pressure, as shown in FIG. 6, by a spring 149 stretched between the crank 139 and a suitable portion of the side plate 98. Accordingly, rotation of the disk shaped control member 133 effects a sliding movement of the link 137 which moves the crank 139 so as to rotate the adjusting member 135, thereby deflecting the depending plate 103 and varying the resisting pressure of the leaf springs 131.

Since the type characters 15 carried on the end of the type bars 19 have different printing areas, it is necessary for the type characters 15 to strike a recording medium on the platen 13 with different impact intensities to effect uniform printing of the different type characters. As previously described in connection with the description of the operation of the type action 11 shown in FIG. 1, the type bars 19 are driven in a printing movement by the engagement of the cam 25 with the power roll 27 thereby driving the sublever 29 rearwardly to pivot the type bars 19 toward the platen 13. The driving movement of the type bar 19 in response to the engagement of the cam 25 with the power roll 27 continues until the rearward end 55 of the cam 25 strikes the stop member 63, whereupon the type bar 19 continues the printing movement to the platen 13 under its own inertia and against the urging of the sublever return spring 51 which reduces the impact intensity of the type character 15.

In accordance with the present invention, the impact intensity for the different type characters may be selectively varied by stretching the return springs 51 to different lengths so as to provide selective reductions in the impact energy imparted to the type bar 19 by the movement of the cam 25 in engagement with the rotat ing power roll 27. To enable the type key action 11 to be assembled as a separate unit for installation between the side plates 98, 99 of the typewriter, the bottom plate 71 of the L-shaped mounting bracket 65, as more particularly shown in FIG. 2, has a rearward extension 151 with a plurality of holes 153 formed in columns, generally indicated 155, and rows, generally indicated 157. Each column 155 of holes 153 is associated with a different type action, and each cow 157 of holes 153 corresponds to a different distance to which the return springs 51 may be stretched. Accordingly, the impact intensity of each type action 11 may be selectively varied by hooking the associated return spring 51 in a selected hole so as to provide the proper tension.

In accordance with still another feature of the present invention, the impact intensity of all the type characters carried by the different type bars 19 may be uniformly adjusted by an impression control mechanism, generally indicated 159, so as to uniformly vary the density of printing of all of the type characters 15. As previously described in connection with the description of the operation of the type action 11 shown in FIG. 1, the type bars 19 are driven in a printing movement until the rearward end 55 of the cam 25 strikes the stop member 63. As more particularly shown in FIG. 8, the stop member 63 forms a part of the impression control mechanism 159 and is in the form of a bail pivotally supported between the side plates 98, 99 and movable between a position enabling maximum engagement of the cam 25 with the power roll 27, as shown in FIG. 9, and a position providing minimum engagement of the cam 25 with the power roll 27, as shown in FIG. 10. The stop member 63 is normally urged to the position of FIG. 9 by a spring 161 stretched between a suitable portion of the side plate 98 and a projection 163 of the bail 63 which extends through an opening 165 in the side plate 98.

To control the setting of the stop member 63, the impression control mechanism 159 includes a control member 167 in the form of a disk rotatably supported about the shaft 115 at the keyboard and connected in controlling relation with the stop member 63 by a link 169. As shown in FIG. 8, one end of the link 169 has a slot 171 formed therein through which the shaft 115 is reveived, and the other end rides under a stub shaft 173 extending laterally from the plate 98 and has a camming surface 175 formed thereon which engages the projection 163 of the stop member 63. The link 169 is urged rearwardly by a spring 177 stretched between a suitable portion of the link 169 and the side plate 98, and a pin 179 projecting laterally from the link 169 is received in a spiraling groove 181 formed in the diskshaped control member 167. Accordingly, the stop member 63 may be moved between the positions of FIGS. 9 and 10 by rotating the control member 167 so as to move the camming surface 175 formedon the link 169.

In accordance with a further feature of the invention, the type action arrangement 11 is provided with a line lock mechanism to prevent the type bars 19 from impacting aginst the platen 13 when a carriage, generally indicated 183, reaches the end of its travel in a line feed direction so as to prevent strikeovers or jamming of the type bars 19. As more particularly shown in FIG. 11, the line lock mechanism includes a bail 185 which is pivotally supported between the side plates 98, 99 and movable from an inoperative position, as shown in FIG. 11, to an operative position, as shown in FIG. 13, for blocking the full engagement of the cams 25 with the power roll 27 to prevent the type bars 19 from being driven in a printing movement to impact against the platen 13. The bail 185 has a crank arm 187 with a laterally projecting pin 189 which is received in a slot 191 formed in one end of a linkage 193 having its other end pivotally connected to one arm of a bell crank 195, and the bail 185 is normally biased to the inoperative position of FIG. 11 by a spring 197 stretched between the other arm of the bell crank 195 and a suitable portion of the side plate 98. As shown, the linkage 193 is slidably supported by a stud shaft 199 which is received in a slot 201 formed in the linkage 193 and upon forward movement of the linkage 193 the bail is urged to the position of FIG. 13 by a spring 203stretched between another arm 205 secured to the bail 185 and a suitable portion of the side plate 98.

The carriage mechanism and the manner in which it operates is more clearly illustrated and described in the previously mentioned copending application entitled Typewriter Carriage Jam Precluding and Action Jam Release Mechanisms.

As is conventional, the typewriter has a center stop 207 which is engaged by a margin stop 209 when the carriage 183 reaches the end of its travel in the letter feed direction. The center stop 207 has a projection 21] extending toward the bell crank 195, and when the center stop is engaged by the margin stop 209, the center stop undergoes a slight movement, as is conventional, which causes the projection 209 to pivot the bell crank 195. The pivoting of the bell crank slides the linkage 193 rearwardly about the stud shaft 199 enabling the bail 185 to move into the blocking position of FIG. 12 under the urging of the spring 203. Accordingly, the earns 25 move into engagement with the power roll 27 by the depression of keylevers 37, will be disengaged by the bail-185 so as to restrict the printing movement of the type bars 19, thereby preventing strikeovers and jamming. When the carriage 183 is subsequently returned to a left margin position, the center stop 207 is returned to its normal position, thereby enabling the linkage 193 to be urged forwardly by the spring 197 causing the bail 185 to be pivoted to the inoperative position of FIG. 12, thereby enabling another line of type to be printed.

What is claimed is:

1. In a powered typewriter having a plurality of type actions each including a sublever movable from a rest position to a print position to effect a printing movement of a type bar, a cam pivotally supported on the sublever and movable into engagement with a power roll to drive the sublever from the rest position to the print position, a trip lever movable to pivot the cam into engagement with the power roll, and a keylever for moving the trip lever to initiate a printing operation, the improvement comprising:

a first pivot rod for pivotally supporting said plurality of sublevers;

a second pivot rod for pivotally supporting said plurality of trip levers;

a third pivot rod for pivotally supporting said plurality of keylevers;

a mounting braclget formour ting said subleyers gid rr'ipieve iid said keylevers in operative relationrelative to each other; said mounting bracket including spaced-apart end plate means having first, second and third holes formed therein for receiving said first, second and third pivot rods respectively in aligned relation to each other; said mounting bracket further including wall means extending between said pair of end plates and having guide slots formed therein for receiving therethrough and operably aligning said sublevers, said trip levers and said keylevers; and said end plates and said wall means defining complementary tabs and tab receiving slots for positioning and securing said end plates and said wall means relative to each other.

2. In a powered typewriter according to claim 1:

said end plates of said mounting bracket having an L-shaped configuration with a top portion, a bottom portion, a front portion and a back portion; and

said wall means of said mounting bracket including a top wall connecting the top portion of said L- shaped end plates, a bottom wall connecting the bottom portions of said L-shaped end plates, an upper front wall connecting said front portions of said L-shaped end plates, and a back wall connecting said back portions of said L-shaped end plates.

3. In a powered typewriter according to claim 1:

said plurality of pivotally supported keylevers each having a finger for contacting an associated trip lever;

said plurality of pivotally supported trip levers each having a first arm for contacting the cam of an associated sublever and a second arm for contacting the finger of an associated keylever; and

a plurality of resilient biasing means each connected between said mounting bracket and a trip lever for urging the second arm against the projecting finger of an associated keylever to pivot said keylever about said third pivot rod.

4. In a powered typewriter according to claim 3, the

combination further comprising:

a keylever control mechanism for limiting the pivotal movement of said plurality of trip levers under the urging of said resilient biasing means and the corresponding pivotal movement of said plurality of keylevers to determine the normal rest position of said plurality of keylevers;

said keylever control mechanism including a stop member extending beside one of the first or second arms of said plurality of trip levers;

said stop member having a cross-sectional configuration in the form of a cam and being rotatably supported for enabling adjustment of the normal rest position of said plurality of keylevers and the distance of keylever movement necessary to move a cam into engagement with a power roll; and

said keylever control mechanism further including a control means connected in controlling relation with said rotatably supported stop member and being manually operable for rotating said stop member.

5. In a powered typewriter according to claim 3, the

combination further comprising:

a pressure control mechanism for adjusting the pressure necessary to pivot said plurality of keylevers to move a cam into enagagement with a power roll;

said pressure control mechanism including spring means in the form of a plurality of leaf springs secured to said mounting bracket adjacent said plurality of trip levers with each leaf spring being associated with a different trip lever and positioned in blocking relation to the path of movement of said trip lever;

said pressure control mechanism further including an adjusting member extending beside said plurality of leaf springs;

said adjusting member having a cross-sectional configuration in the form of a cam and being rotatably supported for bending said plurality of leaf springs to adjust the spring tension resisting pivotal movement of said trip levers; and said pressure control mechanism including a control means connected in controlling relation with said 5 rotatably supported adjusting member and being manually operable for rotating said adjusting member.

6. In a typewriter according to claim 2,-the combination further comprising:

a plurality of return springs each associated with a different one of said plurality of sublevers for resisting the driven movement of said sublevers and urging said sublevers to a rest. position;

said bottom wall of said mounting bracket having an extension in a direction away from said plurality of pivotally supported sublevers;

said extension of said bottom wall having a plurality of holes formed therein and arranged in columns with each column of holes being associated with a different one of said plurality of sublevers; and

said plurality of return springs each being stretched to a selected one of said column of holes associated with each sublever to selectively control the tension of said return spring urging said sublever to a rest position.

7. In a typewriter according to claim 1, the combination further comprising:

an impression control mechanism for uniformly varying the impact intensity of type bars linked to said plurality of sublevers and driven in a printing movement by the engagement of an associated cam with the power roll;

said impression control mechanism including a stop member extending beside the power roll and said cams for limiting the engagement of said cams with the power roll to control the impact intensity of the type bars; I

said stop member being supported for movement from a first position enabling maximum engagement of said cams with the power roll and a second position enabling minimum engagement of said cams with the power roll; and

said impression control mechanism further including a control means connected in controlling relation with said stop member and being manually operable for moving said stop member between said first and second positions.

8. In a typewriter according to claim 1, the combination further comprising:

a line lock mechanism for preventing type bars linked to said sublevers from undergoing a printing movement when a carriage is at a right margin stop position;

said line lock mechanism including a bail extending beside said mounting bracket and the power roll;

said bail being supported for movement between an inoperative position enabling the engagement of said cams with the power roll and blocking position restricting the engagement of said cams with the power roll to prevent the type bars from undergoing a printing movement; and

said line lock means further including linkage means operable in response to the movement of the car riage to a right margin stop position for moving said bail from the inoperative position to the blocking position. 

1. In a powered typewriter having a plurality of type actions each including a sublever movable from a rest position to a print position to effect a printing movement of a type bar, a cam pivotally supported on the sublever and movable into engagement with a power roll to drive the sublever from the rest position to the print position, a trip lever movable to pivot the cam into engagement with the power roll, and a keylever for moving the trip lever to initiate a printing operation, the improvement comprising: a first pivot rod for pivotally supporting said plurality of sublevers; a second pivot rod for pivotally supporting said plurality of trip levers; a third pivot rod for pivotally supporting said plurality of keylevers; a mounting bracket for mounting said sublevers, said trip levers and said keylevers in operative relation relative to each other; said mounting bracket including spaced-apart end plate means having first, second and third holes formed therein for receiving said first, second and third pivot rods respectively in aligned relation to each other; said mounting bracket further including wall means extending between said pair of end plates and having guide slots formed therein for receiving therethrough and operably aligning said sublevers, said trip levers and said keylevers; and said end plates and said wall means defining complementary tabs and tab receiving slots for positioning and securing said end plates and said wall means relative to each other.
 2. In a powered typewriter according to claim 1: said end plates of said mounting bracket having an L-shaped configuration with a top portion, a bottom portion, a front portion and a back portion; and said wall means of said mounting bracket including a top wall connecting the top portion of said L-shaped end plates, a bottom wall connecting the bottom portions of said L-shaped end plates, an upper front wall connecting said front portions of said L-shaped end plates, and a back wall connecting said back portions of said L-shaped end plates.
 3. In a powered typewriter according to claim 1: said plurality of pivotally supported keylevers each having a finger for contacting an associated trip lever; said plurality of pivotally supported trip levers each having a first arm for contacting the cam of an associated sublever and a second arm for contacting the finger of an associated keylever; and a plurality of resilient biasing means each connected between said mounting bracket and a trip lever for urging the second arm against the projecting finger of an associated keylever to pivot said keylever about said third pivot rod.
 4. In a powered typewriter according to claim 3, the combination further comprising: a keylever control mechanism for limiting the pivotal movement of said plurality of trip levers under the urging of said resilient biasing means and the corresponding pivotal movement of said plurality of keylevers to determine the normal rest position of said plurality of keylevers; said keylever control mechanism including a stop member extending beside one of the first or second arms of said plurality of trip levers; said stop member having a cross-sectional configuration in the form of a cam and Being rotatably supported for enabling adjustment of the normal rest position of said plurality of keylevers and the distance of keylever movement necessary to move a cam into engagement with a power roll; and said keylever control mechanism further including a control means connected in controlling relation with said rotatably supported stop member and being manually operable for rotating said stop member.
 5. In a powered typewriter according to claim 3, the combination further comprising: a pressure control mechanism for adjusting the pressure necessary to pivot said plurality of keylevers to move a cam into enagagement with a power roll; said pressure control mechanism including spring means in the form of a plurality of leaf springs secured to said mounting bracket adjacent said plurality of trip levers with each leaf spring being associated with a different trip lever and positioned in blocking relation to the path of movement of said trip lever; said pressure control mechanism further including an adjusting member extending beside said plurality of leaf springs; said adjusting member having a cross-sectional configuration in the form of a cam and being rotatably supported for bending said plurality of leaf springs to adjust the spring tension resisting pivotal movement of said trip levers; and said pressure control mechanism including a control means connected in controlling relation with said rotatably supported adjusting member and being manually operable for rotating said adjusting member.
 6. In a typewriter according to claim 2, the combination further comprising: a plurality of return springs each associated with a different one of said plurality of sublevers for resisting the driven movement of said sublevers and urging said sublevers to a rest position; said bottom wall of said mounting bracket having an extension in a direction away from said plurality of pivotally supported sublevers; said extension of said bottom wall having a plurality of holes formed therein and arranged in columns with each column of holes being associated with a different one of said plurality of sublevers; and said plurality of return springs each being stretched to a selected one of said column of holes associated with each sublever to selectively control the tension of said return spring urging said sublever to a rest position.
 7. In a typewriter according to claim 1, the combination further comprising: an impression control mechanism for uniformly varying the impact intensity of type bars linked to said plurality of sublevers and driven in a printing movement by the engagement of an associated cam with the power roll; said impression control mechanism including a stop member extending beside the power roll and said cams for limiting the engagement of said cams with the power roll to control the impact intensity of the type bars; said stop member being supported for movement from a first position enabling maximum engagement of said cams with the power roll and a second position enabling minimum engagement of said cams with the power roll; and said impression control mechanism further including a control means connected in controlling relation with said stop member and being manually operable for moving said stop member between said first and second positions.
 8. In a typewriter according to claim 1, the combination further comprising: a line lock mechanism for preventing type bars linked to said sublevers from undergoing a printing movement when a carriage is at a right margin stop position; said line lock mechanism including a bail extending beside said mounting bracket and the power roll; said bail being supported for movement between an inoperative position enabling the engagement of said cams with the power roll and blocking position restricting the engagement of said cams with the power roll to prevent the type bars from undergoing a printing movement; and said line lock means further inCluding linkage means operable in response to the movement of the carriage to a right margin stop position for moving said bail from the inoperative position to the blocking position. 